1. Technical Field
The present invention relates to a liquid ejecting head ejecting a liquid from nozzle openings, a liquid ejecting head unit having the liquid ejecting head, a liquid ejecting apparatus and a method of manufacturing the liquid ejecting head.
2. Related Art
As a representative example of liquid ejecting heads discharging liquid droplets, an ink jet recording head discharging ink droplets can be exemplified. As this ink jet recording head, for example, a head has been proposed including a plurality of head main bodies which discharge ink droplets from nozzle openings and a common liquid introduction member (corresponding to a holding member) which is fixed to the plurality of head main bodies and supplies ink from a liquid storage member storing the ink to the head main bodies (for example, see JP-A-2005-225219).
In addition, as the ink jet recording head, a head has been proposed having a circuit board which is connected to a pressure generator such as a piezoelectric element which changes the pressure in a pressure generating chamber of a head main body (for example, see JP-A-2006-272885).
The ink jet recording head of JP-A-2006-272885 holds a circuit board between a casing which holds a flow passage unit (corresponding to the head main body) and an introduction needle unit.
However, when ink adheres to the circuit board, a short circuit or the like occurs in the wiring provided on the circuit board, and an operation failure or a breakdown occurs.
Accordingly, there has been proposed sealing of a circuit board in a plastic casing having an opening which has a size to allow passage of a connecting wiring connected to the circuit board therethrough (for example, see JP-A-2003-11383).
In addition, an ink jet recording head has been proposed which protects a circuit board from ink with an insulating film, an adhesive or the like (for example, see JP-A-2009-978).
However, as in JP-A-2009-978, when the circuit board is protected from ink with an insulating film, an adhesive or the like, an adhesive or the like should be applied to the entire circuit board and the consumption of the adhesive or the like increases. In addition, a problem occurs in that it takes time to provide an adhesive or the like on the circuit board. Further, even when the circuit board is protected with an adhesive, a connector and therearound in which a connecting wiring is connected to the circuit board cannot be protected with the adhesive and a problem occurs in that protection cannot be completely carried out.
In addition, as shown in JP-A-2006-272885 and JP-A-2003-11383, when the circuit board is held in a holding space in a holding member which is divided into two, it is necessary to suppress the invasion of the liquid by sealing this holding space with an adhesive or the like. However, when the holding space is sealed with an adhesive or the like, adhesion failure or adhesion positional deviation occurs due to a foreign substance adhered to the adhesion surface, and connection displacement of flow passages of a head main body, a holding member and a flow passage member such as a needle member fixed to the holding member occurs and the liquid thus leaks, so a problem occurs in that the liquid invades to the inside.
Such problems occur not only in the ink jet recording head but also in a liquid ejecting head ejecting a liquid other than ink.